256 SMITH'S INTERMEDIATE CHEMISTRY 



which do not dissolve in water. It is manufactured by heating 

 coke and sulphur together to a very high temperature. The 

 sulphur (vapor) mixed with the coke combines with the latter, 

 and carbon disulphide passes off as vapor and is condensed. The 

 liquid boils at 46, and is highly inflammable : 



Large quantities are employed in the destruction of prairie 

 dogs and for freeing grain elevators of rats and mice. 



Exercises. 1. Write equations for the union of aluminium 

 and of zinc with sulphur. 



2. What experiments should you use to recognize a piece of 

 sulphur? 



3. In what proportions by volume do, (a) sulphur dioxide and 

 hydrogen sulphide, (6) oxygen and hydrogen sulphide interact? 



4. Write full ionic equations for the precipitation of antimony 

 trisulphide, and for the other double decompositions given in 

 this chapter. 



5. Is heat evolved, or absorbed, when monoclinic sulphur 

 changes over to rhombic sulphur? Is heat evolved, or absorbed, 

 when Sx changes over to S M ? Apply van't Hoff's law (p. 242). 



6. Would equal weights of rhombic and monoclinic sulphur 

 give out equal or different amounts of heat on burning? If differ- 

 ent, which would give the most and which the least? 



7. What would be the effect of passing hydrogen sulphide 

 through a red-hot tube? 



8. Why is chlorine an antidote for hydrogen sulphide poison- 

 ing (see p. 209)? 



